Pigmented purpuric contact dermatitis from Disperse Blue 106 and 124 dyes.

The diagnosis of purpura pigmentosa progressiva in a female patient had to be changed to purpuric contact dermatitis after patch testing with textile dyes. A modified patch test performed in the area in which most of her skin lesions were located revealed a petechial reaction to the azo dye Disperse Blue 124/106. For evaluation of purpura pigmentosa progressiva we suggest a patch test with potential allergens, and, especially for textile dyes, a patch test at the lesion site may be helpful.